Researchers at Hof University of Applied Sciences are currently focusing on a particularly exciting and versatile plant: The Institute of Materials Science (ifm) in Münchberg is focusing on the willow shrub. Due to the flexible properties of its wood, its rods can be used in textile production, the construction industry, but also in medicine and cosmetics. The willow thus provides a very rapidly renewable raw material which, when used in the above-mentioned areas, also results in highCO2 savings.
Willow has the best properties for the intended fields of application in the textile and construction industries: On the one hand, it is so flexible that endless willow wood threads can be interwoven or woven and used, for example, as a substitute for rattan, which is made from the East Asian rotang palm. On the other hand, the interwoven and woven wood is so stable that it can also be used to reinforce facades in the construction sector.
We want to firmly establish willow wood as a material for these areas. The advantages are obvious: the shrub is fast-growing and rods up to five meters long can be harvested every year. And the use of willow also helps to reduceCO2 emissions – simply because it is a regional wood that does not have to be transported to us first.”
Corinna Anzer, ifm
She continues: “Together with our partner, the University of Kassel – research platform BAU KUNST ERFINDEN, we have set ourselves the goal of reliably replacing the familiar manual braiding and weaving process with industrial, i.e. mechanical, processes. To this end, we have converted various machines in our textile processing department.” Further concrete applications for the finished product are expected to arise in the fields of architecture, interior design, furniture design, sport and lampshades.
Sustainable production of a regional wood
In their research, the scientists are also initially working with farmers and industrial companies on sustainable production, i.e. the cultivation of willows with very specific material and growth characteristics. They are cultivating the shrub in so-called multifunctional agroforestry systems. Woody plants are combined with arable crops and animal husbandry in such a way that ecological and economic benefits are created for the farmer. Corinna Anzer, Head of Weaving and Lichens at ifm, explains:
‘The aim is to use the wood to obtain the raw material for willow wood threads and willow wood textile. At the same time, we extract salicylates from the bark of the rods, which can be used in medicine and cosmetics. The willow can therefore be used and processed in many different ways.”
Corinna Anzer, ifm
For farmers interested in production, the shrub also has another advantage: the willow is a deep-rooted plant and is therefore more resistant to short periods of drought. It also provides good erosion protection with its deep root system in the soil.
Research into work steps
Of course, research into the processing of willow wood threads also involves many challenges: first of all, the dried willow rods, which are several meters long, have to be processed into a uniform thread. They are processed in width and thickness to achieve a constant cross-section. In a further step, the individual sections are “scarfed”, i.e. cut at an acute angle, in order to obtain areas that can be easily glued together. “This is a particularly important work step, because the gluing point must not be a weak point later on,” says Corinna Anzer, explaining the difficulty. After all, the braiding and weaving process depends on the precise balancing of machine parameters and thread tension to prevent the material from tearing.
The necessary deflections of the thread at a 180-degree angle were particularly challenging for the researchers – after all, although willow is comparatively flexible for wood, it is not as flexible as cotton, polyester or hemp. The weaving process itself can technically be imagined as a classic dance under the maypole: “Just as the colorful ribbons overlap at the maypole dance, our willow wood threads must also arrange themselves in order to form a resilient structure,” says the deputy project manager.
Analysis along the value chain
Furthermore, the entire value chain of willow wood from cultivation to the highly refined product is also analyzed – whereby soils, climate, water balance and biodiversity-promoting measures are also taken into account and recorded. The underlying projects were and are funded and supported by the Federal Institute for Research on Building, Urban Affairs and Spatial Development (BBSR) on behalf of the Federal Ministry of Housing, Urban Development and Building (BMWSB) with funds from the Zukunft Bau innovation program and the Fachagentur Nachwachsende Rohstoffe e.V. on behalf of the Federal Ministry of Food and Agriculture (BMEL).
